perf test: Add sched latency and script shell tests

Add shell tests covering the `perf sched latency` and `perf sched
script` commands. The test creates 2 noploop processes on the same
forced CPU, it then checks that the process appears in the `perf
sched` output.

Reviewed-by: James Clark <james.clark@linaro.org>
Signed-off-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250628012302.1242532-2-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>

tools/perf/tests/shell/sched.sh

@@ -0,0 +1,93 @@
+#!/bin/bash
+# perf sched tests
+# SPDX-License-Identifier: GPL-2.0
+
+set -e
+
+if [ "$(id -u)" != 0 ]; then
+  echo "[Skip] No root permission"
+  exit 2
+fi
+
+err=0
+perfdata=$(mktemp /tmp/__perf_test_sched.perf.data.XXXXX)
+PID1=0
+PID2=0
+
+cleanup() {
+  rm -f "${perfdata}"
+  rm -f "${perfdata}".old
+
+  trap - EXIT TERM INT
+}
+
+trap_cleanup() {
+  echo "Unexpected signal in ${FUNCNAME[1]}"
+  cleanup
+  exit 1
+}
+trap trap_cleanup EXIT TERM INT
+
+start_noploops() {
+  # Start two noploop workloads on CPU0 to trigger scheduling.
+  perf test -w noploop 10 &
+  PID1=$!
+  taskset -pc 0 $PID1
+  perf test -w noploop 10 &
+  PID2=$!
+  taskset -pc 0 $PID2
+
+  if ! grep -q 'Cpus_allowed_list:\s*0$' "/proc/$PID1/status"
+  then
+    echo "Sched [Error taskset did not work for the 1st noploop ($PID1)]"
+    grep Cpus_allowed /proc/$PID1/status
+    err=1
+  fi
+
+  if ! grep -q 'Cpus_allowed_list:\s*0$' "/proc/$PID2/status"
+  then
+    echo "Sched [Error taskset did not work for the 2nd noploop ($PID2)]"
+    grep Cpus_allowed /proc/$PID2/status
+    err=1
+  fi
+}
+
+cleanup_noploops() {
+  kill "$PID1" "$PID2"
+}
+
+test_sched_latency() {
+  echo "Sched latency"
+
+  start_noploops
+
+  perf sched record --no-inherit -o "${perfdata}" sleep 1
+  if ! perf sched latency -i "${perfdata}" | grep -q perf-noploop
+  then
+    echo "Sched latency [Failed missing output]"
+    err=1
+  fi
+
+  cleanup_noploops
+}
+
+test_sched_script() {
+  echo "Sched script"
+
+  start_noploops
+
+  perf sched record --no-inherit -o "${perfdata}" sleep 1
+  if ! perf sched script -i "${perfdata}" | grep -q perf-noploop
+  then
+    echo "Sched script [Failed missing output]"
+    err=1
+  fi
+
+  cleanup_noploops
+}
+
+test_sched_latency
+test_sched_script
+
+cleanup
+exit $err